The effect of different GNPs addition on the electrical conductivities and percolation thresholds of the SiAlON matrix composites

Insulating SiAlON ceramics may become electrically conductive with the addition of a conductive phase such as GNPs and can be used more widely. However, the differences in the properties of the used GNPs significantly affect the amount of electrical conductivity that they provide to the matrix. In this study, four different GNPs with different properties such as lateral dimension, thickness and aspect ratio were added to SiAlON in the amount of 1.5, 2, 3 and 4 wt. % and the effects of different properties on the conductivity of composites were investigated. The thinnest GNPs with largest dimension and aspect ratio among the used GNPs provided the highest electrical conductivity and lowest percolation thresholds to SiAlON. The decrease in dimension, aspect ratios and the increase in thickness decreased the electrical conductivity of GNPs. Composites exhibited anisotropic behavior with better conductivity and percolation threshold values in the in-plane direction than through-plane direction.